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Abstract:

A gear-shift control apparatus comprises: a shift-hold-level-calculation
unit for calculating, in accordance with operation of a driver, a shift
hold level that varies between 0% representing a complete automatic
transmission state and 100% representing a complete manual transmission
state; and a gear-shift processing unit for performing gear-shift control
processing for an automatic transmission in accordance with the shift
hold level calculated by the shift-hold-level-calculation unit.

Claims:

1. A gear-shift control apparatus for an automatic transmission,
comprising: a shift-hold-level-calculation unit that calculates a shift
hold level that indicates a predetermined value to hold a shift gear
according to operation by a driver; and a gear-shift processing unit that
controls shifting of an automatic transmission based on the shift hold
level that was calculated by an shift-hold-level-calculation unit,
wherein said shift hold level is continuously updated between 0%
representing a complete automatic transmission state and 100%
representing a complete manual transmission state.

2. The gear-shift control apparatus for an automatic transmission
according to claim 1, wherein the shift-hold-level-calculation unit
performs calculation so that the shift hold level is forcibly changed to
100% when an ON operation is performed by a shift switch or a shift
lever; and the gear-shift processing unit performs gear-shift control of
the automatic transmission when an ON operation is performed by the shift
switch or shift lever.

3. The gear-shift control apparatus for an automatic transmission
according to claim 1, wherein the gear-shift control apparatus comprises
a sensor that detects accelerator opening degree; and the
shift-hold-level-calculation unit performs calculation so that when the
accelerator opening degree that is detected by the sensor is equal to or
greater than a threshold value, and the shift hold level is greater than
0%, the shift hold level is changed so as to approach 0%; and performs
calculation so that when the accelerator opening degree that is detected
by the sensor is less than the threshold value, and the shift hold level
is greater than 0% and less than 100%, the shift hold level is changed so
as to approach 100%.

4. The gear-shift control apparatus for an automatic transmission
according to claim 1, wherein the gear-shift control apparatus comprises
a sensor that detects accelerator opening degree; and the
shift-hold-level-calculation unit performs calculation so that when the
accelerator opening degree that is detected by the sensor is equal to or
greater than a threshold value, and the shift hold level is greater than
0%, the shift hold level is changed according to the amount of change in
the accelerator opening degree; and performs calculation so that when the
accelerator opening degree that is detected by the sensor is less than
the threshold value, and the shift hold level is greater than 0% and less
than 100%, the shift hold level is changed so as to approach 100%.

5. The gear-shift control apparatus for an automatic transmission
according to claim 1, wherein the gear-shift control apparatus comprises
a sensor that detects the accelerator opening degree; and the
shift-hold-level-calculation unit calculates, based on vehicle speed and
gradient of a road, an upper-limit value and a lower-limit value for the
accelerator opening degree necessary for a vehicle to travel at a
constant speed; performs calculation so that when the accelerator opening
degree that is detected by the sensor is equal to or greater than
upper-limit value, and the shift hold level is greater than 0% and less
than 100%, the shift hold level is changed according to a difference
between the accelerator opening degree and the upper-limit value, and the
amount of change in the accelerator opening degree; performs calculation
so that when the accelerator opening degree is between the upper-limit
value and the lower-limit value, and the shift hold level is greater than
0% and less than 100%, the shift hold level is changed according to the
amount of change in the accelerator opening degree; and performs
calculation so that when the accelerator opening degree is equal to or
less then the lower-limit value, and the shift hold level is greater than
0% and less than 100%, the shift hold level is changed according to a
difference between the accelerator opening degree and the lower-limit
value, and an absolute value of the amount of change in the accelerator
opening degree.

6. The gear-shift control apparatus for an automatic transmission
according to claim 1, wherein the gear-shift control apparatus comprises
a sensor that detects accelerator opening degree; and the gear-shift
processing unit, based on the shift hold level that was calculated by the
shift-hold-level calculation unit, selects a corresponding shifting line
from among a plurality of preset shifting lines, and based on the
selected shifting line, performs gear-shift control according to the
accelerator opening degree detected by the sensor, and vehicle speed.

7. The gear-shift control apparatus for an automatic transmission
according to claim 5, wherein the gear-shift control apparatus comprises
a sensor that detects accelerator opening degree; and the gear-shift
processing unit, based on a plurality of preset shifting lines,
calculates shifting point(s) according to the shift hold level that was
calculated by the shift-hold-level-calculation unit, and the accelerator
opening degree that was detected by the sensor, and selects a
corresponding shifting line from among a plurality of preset shifting
lines, and based on the calculated shifting point(s), performs gear-shift
control according to vehicle speed.

8. The gear-shift control apparatus for an automatic transmission
according to claim 1, wherein the gear-shift control apparatus comprises
a sensor that detects accelerator opening degree; and the gear-shift
processing unit, based on the shift hold level that was calculated by the
shift-hold-level-calculation unit, corrects the accelerator opening
degree that was detected by the sensor, and based on preset shifting
lines, performs gear-shift control according to the corrected accelerator
opening degree and vehicle speed.

9. The gear-shift control apparatus for an automatic transmission
according to claim 2, wherein the gear-shift control apparatus comprises
a sensor that detects accelerator opening degree; and the
shift-hold-level-calculation unit performs calculation so that when the
accelerator opening degree that is detected by the sensor is equal to or
greater than a threshold value, and the shift hold level is greater than
0%, the shift hold level is changed so as to approach 0%; and performs
calculation so that when the accelerator opening degree that is detected
by the sensor is less than the threshold value, and the shift hold level
is greater than 0% and less than 100%, the shift hold level is changed so
as to approach 100%.

10. The gear-shift control apparatus for an automatic transmission
according to claim 2, wherein the gear-shift control apparatus comprises
a sensor that detects accelerator opening degree; and the
shift-hold-level-calculation unit performs calculation so that when the
accelerator opening degree that is detected by the sensor is equal to or
greater than a threshold value, and the shift hold level is greater than
0%, the shift hold level is changed according to the amount of change in
the accelerator opening degree; and performs calculation so that when the
accelerator opening degree that is detected by the sensor is less than
the threshold value, and the shift hold level is greater than 0% and less
than 100%, the shift hold level is changed so as to approach 100%.

11. The gear-shift control apparatus for an automatic transmission
according to claim 2, wherein the gear-shift control apparatus comprises
a sensor that detects the accelerator opening degree; and the
shift-hold-level-calculation unit calculates, based on vehicle speed and
gradient of a road, an upper-limit value and a lower-limit value for the
accelerator opening degree necessary for a vehicle to travel at a
constant speed; performs calculation so that when the accelerator opening
degree that is detected by the sensor is equal to or greater than
upper-limit value, and the shift hold level is greater than 0% and less
than 100%, the shift hold level is changed according to a difference
between the accelerator opening degree and the upper-limit value, and the
amount of change in the accelerator opening degree; performs calculation
so that when the accelerator opening degree is between the upper-limit
value and the lower-limit value, and the shift hold level is greater than
0% and less than 100%, the shift hold level is changed according to the
amount of change in the accelerator opening degree; and performs
calculation so that when the accelerator opening degree is equal to or
less then the lower-limit value, and the shift hold level is greater than
0% and less than 100%, the shift hold level is changed according to a
difference between the accelerator opening degree and the lower-limit
value, and an absolute value of the amount of change in the accelerator
opening degree.

12. The gear-shift control apparatus for an automatic transmission
according to claim 2, wherein the gear-shift control apparatus comprises
a sensor that detects accelerator opening degree; and the gear-shift
processing unit, based on the shift hold level that was calculated by the
shift-hold-level calculation unit, selects a corresponding shifting line
from among a plurality of preset shifting lines, and based on the
selected shifting line, performs gear-shift control according to the
accelerator opening degree detected by the sensor, and vehicle speed.

13. The gear-shift control apparatus for an automatic transmission
according to claim 3, wherein the gear-shift control apparatus comprises
a sensor that detects accelerator opening degree; and the gear-shift
processing unit, based on the shift hold level that was calculated by the
shift-hold-level calculation unit, selects a corresponding shifting line
from among a plurality of preset shifting lines, and based on the
selected shifting line, performs gear-shift control according to the
accelerator opening degree detected by the sensor, and vehicle speed.

14. The gear-shift control apparatus for an automatic transmission
according to claim 4, wherein the gear-shift control apparatus comprises
a sensor that detects accelerator opening degree; and the gear-shift
processing unit, based on the shift hold level that was calculated by the
shift-hold-level calculation unit, selects a corresponding shifting line
from among a plurality of preset shifting lines, and based on the
selected shifting line, performs gear-shift control according to the
accelerator opening degree detected by the sensor, and vehicle speed.

15. The gear-shift control apparatus for an automatic transmission
according to claim 5, wherein the gear-shift control apparatus comprises
a sensor that detects accelerator opening degree; and the gear-shift
processing unit, based on the shift hold level that was calculated by the
shift-hold-level calculation unit, selects a corresponding shifting line
from among a plurality of preset shifting lines, and based on the
selected shifting line, performs gear-shift control according to the
accelerator opening degree detected by the sensor, and vehicle speed.

16. The gear-shift control apparatus for an automatic transmission
according to claim 2, wherein the gear-shift control apparatus comprises
a sensor that detects accelerator opening degree; and the gear-shift
processing unit, based on a plurality of preset shifting lines,
calculates shifting point(s) according to the shift hold level that was
calculated by the shift-hold-level-calculation unit, and the accelerator
opening degree that was detected by the sensor, and selects a
corresponding shifting line from among a plurality of preset shifting
lines, and based on the calculated shifting point(s), performs gear-shift
control according to vehicle speed.

17. The gear-shift control apparatus for an automatic transmission
according to claim 3, wherein the gear-shift control apparatus comprises
a sensor that detects accelerator opening degree; and the gear-shift
processing unit, based on a plurality of preset shifting lines,
calculates shifting point(s) according to the shift hold level that was
calculated by the shift-hold-level-calculation unit, and the accelerator
opening degree that was detected by the sensor, and selects a
corresponding shifting line from among a plurality of preset shifting
lines, and based on the calculated shifting point(s), performs gear-shift
control according to vehicle speed.

18. The gear-shift control apparatus for an automatic transmission
according to claim 4, wherein the gear-shift control apparatus comprises
a sensor that detects accelerator opening degree; and the gear-shift
processing unit, based on a plurality of preset shifting lines,
calculates shifting point(s) according to the shift hold level that was
calculated by the shift-hold-level-calculation unit, and the accelerator
opening degree that was detected by the sensor, and selects a
corresponding shifting line from among a plurality of preset shifting
lines, and based on the calculated shifting point(s), performs gear-shift
control according to vehicle speed.

19. The gear-shift control apparatus for an automatic transmission
according to claim 5, wherein the gear-shift control apparatus comprises
a sensor that detects accelerator opening degree; and the gear-shift
processing unit, based on a plurality of preset shifting lines,
calculates shifting point(s) according to the shift hold level that was
calculated by the shift-hold-level-calculation unit, and the accelerator
opening degree that was detected by the sensor, and selects a
corresponding shifting line from among a plurality of preset shifting
lines, and based on the calculated shifting point(s), performs gear-shift
control according to vehicle speed.

20. The gear-shift control apparatus for an automatic transmission
according to claim 2, wherein the gear-shift control apparatus comprises
a sensor that detects accelerator opening degree; and the gear-shift
processing unit, based on the shift hold level that was calculated by the
shift-hold-level-calculation unit, corrects the accelerator opening
degree that was detected by the sensor, and based on preset shifting
lines, performs gear-shift control according to the corrected accelerator
opening degree and vehicle speed.

Description:

TECHNICAL FIELD

[0001] This application claims priority based on Japanese Patent
Application No 2010-071248 filed on Mar. 26, 2010, the entire disclosure
of the aforesaid application being incorporated herein by reference
thereto. The present invention relates to a gear-shift control apparatus
for an automatic transmission that is capable of switching between an
automatic-transmission mode and a manual-transmission mode.

BACKGROUND

[0002] In recent years, there are automatic transmissions that, in
addition to an automatic-transmission mode that automatically changes
speeds according to the state (conditions) of the vehicle (for example,
the vehicle speed, throttle opening, and the like), is provided with a
manual-transmission mode in which the driver shifts gears using manual
operation. Switching between the automatic-transmission mode and the
manual-transmission mode of this kind of automatic transmission is
performed manually by the driver.

[0003] For example, in the gear-shift control apparatus for an automatic
transmission disclosed in Patent Literature 1, an apparatus is disclosed
wherein switching between the automatic-transmission mode and the
manual-transmission mode can be selectively performed based on a
switching signal from a transmission-mode switch, and when a down-shift
operation switch that is provided on a steering wheel is operated while
in the automatic-transmission mode, the transmission mode is switched to
the manual-transmission mode; then after that, when an up-shift switch
for returning to the automatic-transmission mode that is provided on a
steering wheel is operated while in the manual-transmission mode, the
transmission mode is switched to the automatic-transmission mode. By this
provision, the driver is able to switch between the
automatic-transmission mode and manual-transmission mode without having
to remove his/her hands from the steering wheel, and thus it is possible
to improve the ease of operation and safety of the shifting operation.

[0004] Moreover, in the gear-shift control apparatus for an automatic
transmission disclosed in Patent Literature 2, an apparatus is disclosed
that, together with being provided with an automatic-transmission control
method that sets a target transmission gear ratio according to the
vehicle speed and engine load, is provided with an up-shifting
instruction method and down-shifting instruction method that give
instructions for up-shifting or down-shifting according to operation by
the driver, a manual-transmission control method that sets a target
transmission gear ratio based on a signal from the up-shifting
instruction method or down-shifting instruction method, and a
transmission mode switching method that selectively switches between the
automatic-transmission mode and manual-transmission mode; wherein, when
the up-shifting instruction method and the down-shifting instruction
method are operated at the same time, the transmission-mode switching
method selectively switches between the automatic-transmission mode and
the manual-transmission mode. As a result, it is possible for the driver
to switch the transmission mode without having to take his/her hands off
of the steering wheel. [0005] [Patent Literature 1] Japanese Patent
Application No. 2002-349687 [0006] [Patent Literature 2] Japanese Patent
Application No. H9-203457

SUMMARY

[0007] The entire contents of the aforesaid Patent Literatures 1 and 2 are
incorporated herein by reference thereto. The following analysis is given
in accordance to the present invention.

[0008] In the shift control apparatus for an automatic transmission
according to Patent Literatures 1 and 2, it is necessary for the driver
to perform some kind operation when switching from the
manual-transmission (manual) mode to the automatic-transmission mode, so
the following problems exist. For example, there is an occurrence where a
vehicle may travel unnecessarily in a low gear because the driver forgot
to return to the automatic-transmission mode, so there is a possibility
that fuel efficiency will become poor. Moreover, in a case such as where
it is desired to perform an engine brake by down-shifting manually before
turning at a corner, and then to automatically shift after making the
turn at the corner, it is always necessary for the driver to perform a
specified operation to return to the automatic-transmission mode after
coming out of the turn, so the operation becomes troublesome.

[0009] Furthermore, in the gear-shift control apparatus for an automatic
transmission according to Patent Literatures 1 and 2, for example, when
switching to the automatic-transmission mode in a situation such as when
the vehicle is traveling at a high speed (for example, a vehicle speed at
which a vehicle would be traveling in 5th gear in the case of an
automatic transmission) in the manual-transmission (manual) mode and the
transmission speed is held in a low gear (for example 2nd gear), shifting
from 2nd gear to 5th gear is performed at once, so the following problems
exist. For example, in the case of a vehicle that is traveling at
constant speed in 2nd gear, by shifting to 5th gear by switching from the
manual-transmission mode to the automatic-transmission mode, the engine
rotational speed (rpm) suddenly drops, and the engine torque suddenly
increases, so it becomes necessary to adjust acceleration, so drivability
and the handling feel worsen. Moreover, in the case of accelerating in
2nd gear, by shifting to 5th gear by switching from the
manual-transmission mode to the automatic-transmission mode, the drive
power is suddenly lost and the acceleration power suddenly drops, so
drivability worsens. In the case of reducing speed in 2nd gear (engine
brake), by shifting to 5th gear by shifting from the manual-transmission
mode to the automatic-transmission mode, the engine brake is suddenly
lost, and the deceleration power suddenly drops, so drivability worsens.

[0010] Moreover, in the gear-shift control apparatus for an automatic
transmission according to Patent Literatures 1 and 2, it is necessary to
provide control for both the automatic-transmission mode and the
manual-transmission (manual) mode, so control becomes complex.

[0011] Furthermore, in the gear-shift control apparatus for an automatic
transmission according to Patent Literature 1, the operation of the
up-shifting switch causes switching to the automatic-transmission mode,
so it is not possible to up-shift as in the manual-transmission mode,
which offers inconvenience.

[0012] The object of the present invention is to provide a gear-shift
control apparatus for an automatic transmission that is capable of
switching between the automatic-transmission mode and the
manual-transmission mode while at the same time is capable of improving
ease of operation, fuel efficiency, drivability and convenience, and
simplifying control.

[0013] A gear-shift control apparatus for an automatic transmission
according to a first aspect of the present invention, comprises: a
shift-hold-level-calculation unit that calculates a shift hold level that
varies between 0% representing a complete automatic transmission state
and 100% representing a complete manual transmission state according to
operation by a driver; and a gear-shift processing unit that controls
shifting of an automatic transmission based on the shift hold level that
was calculated by the shift-hold-level-calculation unit.

[0014] In the gear-shift control apparatus for an automatic transmission
of the present invention, preferably the shift-hold-level-calculation
unit performs calculation so that the shift hold level is forcibly
changed to 100% when an ON operation is performed by a shift switch or a
shift lever; and the gear-shift processing unit performs gear-shift
control of the automatic transmission when an ON operation is performed
by the shift switch or shift lever.

[0015] In the gear-shift control apparatus for an automatic transmission
of the present invention, preferably the gear-shift control apparatus
comprises a sensor that detects the accelerator opening degree (i.e.,
position); and the shift-hold-level-calculation unit performs calculation
so that when the accelerator opening degree that is detected by the
sensor is equal to or greater than a threshold value, and the shift hold
level is greater than 0%, the shift hold level is changed so as to
approach (i.e., in a direction toward) 0%; and performs calculation so
that when the accelerator opening degree that is detected by the sensor
is less than the threshold value, and the shift hold level is greater
than 0% and less than 100%, the shift hold level is changed so as to
approach (i.e., in a direction toward) 100%.

[0016] In the gear-shift control apparatus for an automatic transmission
of the present invention, preferably the gear-shift control apparatus
comprises a sensor that detects the accelerator opening degree; and the
shift-hold-level-calculation unit performs calculation so that when the
accelerator opening degree that is detected by the sensor is equal to or
greater than a threshold value, and the shift hold level is greater than
0%, the shift hold level is changed so as to approach (i.e., in a
direction toward) 0% according to the amount of change in the accelerator
opening degree; and performs calculation so that when the accelerator
opening degree that is detected by the sensor is less than the threshold
value, and the shift hold level is greater than 0% and less than 100%,
the shift hold level is changed so as to approach (i.e., in a direction
toward) 100%.

[0017] In the gear-shift control apparatus for an automatic transmission
of the present invention, preferably the gear-shift control apparatus
comprises a sensor that detects the accelerator opening degree; and the
shift-hold-level-calculation unit calculates, based on vehicle speed and
gradient (incline) of the road, an upper-limit value and a lower-limit
value for the accelerator opening degree necessary for a vehicle to
travel at constant speed; performs calculation so that when the
accelerator opening degree that is detected by the sensor is equal to or
greater than upper-limit value, and the shift hold level is greater than
0% and less than 100%, the shift hold level is changed according to a
difference between the accelerator opening degree and the upper-limit
value, and the amount of change in the accelerator opening degree;
performs calculation so that when the accelerator opening degree is
between the upper-limit value and the lower-limit value, and the shift
hold level is greater than 0% and less than 100%, the shift hold level is
changed according to the amount of change in the accelerator opening
degree; and performs calculation so that when the accelerator opening
degree is equal to or less then the lower-limit value, and the shift hold
level is greater than 0% and less than 100%, the shift hold level is
changed according to a difference between the accelerator opening degree
and the lower-limit value, and an absolute value of the amount of change
in the accelerator opening degree.

[0018] In the gear-shift control apparatus for an automatic transmission
of the present invention, preferably the gear-shift control apparatus
comprises a sensor that detects the accelerator opening degree; and the
gear-shift processing unit, based on the shift hold level that was
calculated by the shift-hold-level calculation unit, selects a
corresponding shifting line from among a plurality of preset shifting
lines, and based on the selected shifting line, performs gear-shift
control according to the accelerator opening degree detected by the
sensor, and vehicle speed.

[0019] In the gear-shift control apparatus for an automatic transmission
of the present invention, preferably the gear-shift control apparatus
comprises a sensor that detects the accelerator opening degree; and the
gear-shift processing unit, based on a plurality of preset shifting
lines, calculates shifting points according to the shift hold level that
was calculated by the shift-hold-level-calculation unit, and the
accelerator opening degree that was detected by the sensor, and selects a
corresponding shifting line from among a plurality of preset shifting
lines, and based on the calculated shifting point(s), performs gear-shift
control according to vehicle speed.

[0020] In the gear-shift control apparatus for an automatic transmission
of the present invention, preferably the gear-shift control apparatus
comprises a sensor that detects the accelerator opening degree; and the
gear-shift processing unit, based on the shift hold level that was
calculated by the shift-hold-level-calculation unit, corrects the
accelerator opening degree that was detected by the sensor, and based on
preset shifting lines, performs gear-shift control according to the
corrected accelerator opening degree and vehicle speed.

[0021] With the present invention, the switching-over of transmission
modes is performed automatically according to a shift hold level that is
calculated and set automatically, so there is no need for troublesome
operation when changing modes, and it is possible to improve operability
and fuel efficiency. Moreover, switching the transmission mode is
performed in multi-stages or continuously according to a shift hold level
that is calculated and set automatically, so there is no such change
(sudden shifting) of the state (running conditions) of the vehicle, and
thus it is possible to improve drivability and feeling. In addition,
shifting can be achieved by improving just the automatic transmission
control without having to provide a new manual shifting control by
manipulating a shift switch or shift lever, so control can be simplified.
Furthermore, with the operation of a shift switch or a shift lever, it is
possible to hold shifting, and thus it is possible to improve operability
and convenience.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]FIG. 1 is a block diagram schematically illustrating the
construction of a vehicle that includes the gear-shift control apparatus
for an automatic transmission of a first example of the present
invention,

[0023]FIG. 2 is a time chart for explaining the change in the shift hold
level that is calculated by the gear-shift control apparatus for an
automatic transmission of a first example of the present invention,

[0024]FIG. 3 is a drawing of an image of shifting lines that are used in
the gear-shift control apparatus for an automatic transmission of a first
example of the present invention,

[0025]FIG. 4 is a flowchart that schematically illustrates the operation
of the gear-shift control apparatus for an automatic transmission of a
first example of the present invention,

[0026]FIG. 5 is a drawing for explaining shifting points that are
calculated by the gear-shift control apparatus for an automatic
transmission of a second example of the present invention,

[0027]FIG. 6 is a drawing for explaining correction of the accelerator
opening degree by the gear-shift control apparatus for an automatic
transmission of a third example of the present invention,

[0028] FIG. 7 is a time chart for explaining the change in the shift hold
level that is calculated by the gear-shift control apparatus for an
automatic transmission of a fourth example of the present invention,

[0029]FIG. 8 is a block diagram that schematically illustrates the
construction of a vehicle that includes the gear-shift control apparatus
for an automatic transmission of a fifth example of the present
invention, and

[0030]FIG. 9 is a time chart for explaining the change in the shift hold
level that is calculated by the gear-shift control apparatus for an
automatic transmission of a fifth example of the present invention.

PREFERRED MODES

[0031] The shift control apparatus for an automatic transmission of a
first exemplary embodiment of the present invention comprises: a
shift-hold-level-calculation unit (7a in FIG. 1) that calculates the
shift hold level that varies between 0%, which indicates a state of
complete automatic shifting, and 100%, which indicates a state of
complete manual shifting; and a gear-shift processing unit (7b in FIG. 1)
that processes shift control of an automatic transmission (2 in FIG. 1)
based on the shift hold level that was calculated by the
shift-hold-level-calculation unit.

[0032] Assigning reference numbers in the drawings of this description is
solely for the purpose of aiding in understanding the invention, and it
is not intended to limit to the mode illustrated in the drawing.

Example 1

[0033] The shift control apparatus for an automatic transmission of a
first example of the present invention is explained using the drawings.
FIG. 1 is a block diagram that schematically illustrates the construction
of a vehicle that includes the gear-shift control apparatus for an
automatic transmission of this first example of the present invention.
FIG. 2 is a time chart for explaining the change in the shift hold level
that is calculated by the gear-shift control apparatus for an automatic
transmission of this first example of the present invention. FIG. 3 is a
drawing illustrating an image of shifting lines that are used by the
gear-shift control apparatus for an automatic transmission of this first
example of the present invention.

[0034] In referencing FIG. 1, the vehicle that includes the gear-shift
control apparatus for an automatic transmission is provided with an
automatic transmission 2 and differential gear 3 in the power
transmission path between an engine and drive wheels 4, 5. The vehicle
has an engine 1, an automatic transmission 2, a differential gear 3,
drive wheels 4, 5, an electronic controller 7, and accelerator opening
degree (position) sensor 11, vehicle speed sensor 12, a shift position
sensor 13 and a steering wheel 20. In FIG. 1, a vehicle having only the
engine 1 as a power source is illustrated, however, the invention could
also be applied to a hybrid vehicle that has an engine and a motor as
power sources, or an electric automobile that has only a motor as a power
source.

[0035] The engine 1 is an internal combustion engine that explosively
combusts fuel inside the cylinder and outputs torque by that thermal
energy, and has an injector actuator (not illustrated in the figure) that
adjusts the amount of fuel injection, and an igniter actuator (not
illustrated in the figure) that adjusts the ignition timing for igniting
the fuel. The torque of the engine 1 is transmitted to the automatic
transmission 2 by way of a crankshaft. The engine 1 is connected to an
engine controller (not illustrated in the figure) so that communication
is possible, and is controlled by the engine controller.

[0036] The automatic transmission 2 is a mechanism that transmits the
rotational power (torque) outputted from the engine 1 with changing in
rotational speed (gear shifting), and is a mechanism that transmits that
torque to the drive wheels 4, 5 by way of the differential gear 3. The
automatic transmission 2, for example, is such that the torque that is
outputted from the engine 1 is inputted to a planetary gear mechanism (a
combination of a plurality of planetary gear mechanisms) by way of a
torque converter (not illustrated in the figure), and that torque is
changed in speed by the planetary gear mechanism and outputted to the
differential gear 3. The automatic transmission 2 has a clutch that
causes specified rotating elements of the planetary gear mechanism to
engage such that they can be disconnected or connected, a brake(s) that
stops the rotation of specified rotating elements, a hydraulic circuit
that controls the hydraulics of the clutch and brake(s), and solenoids
that switch the hydraulic path or adjust the hydraulic pressure in a
hydraulic circuit. The automatic transmission 2 is connected with the
electronic controller 7 so that communication is possible, and is
controlled by the electronic controller 7.

[0037] The electronic controller 7 is (comprises) a computer that controls
operation of the automatic transmission 2. The electronic controller 7
forms the gear-shift control apparatus. The electronic controller 7 is
connected to various actuators (for example, solenoids not illustrated in
the figure), various sensors 11 to 13, and switches 21, 22 of the
automatic transmission 2 so that communication is possible. The
electronic controller 7 performs control based on specified programs
(including databases, maps and the like) according to signals from the
sensors 11 to 13, switches 21, 22 etc. The shift-hold-level-calculation
unit 7a, the gear-shift processing unit 7b, and a memory 7c are
implemented by the electronic controller 7 executing programs.

[0038] The shift-hold-level-calculation unit 7a is a unit that has a
function for calculating the shift hold level. The
shift-hold-level-calculation unit 7a calculates the shift hold level
based on the state (conditions) of the vehicle (for example, vehicle
speed) or operation (manipulation) by a driver (for example, accelerator
etc.) according to signals from the sensors 11 to 13 and switches 21, 22.
The shift-hold-level-calculation unit 7a performs calculation so that the
level decreases toward 0% in certain conditions (for example, a condition
in which the vehicle speed, accelerator opening degree are both
continuously constant) under which returning to the normal automatic
transmission state is allowable (automatic-transmission mode), and
performs calculation so that the level increases toward 100% in another
conditions (for example, when accelerator is always changing such as when
travelling over a winding road) in which shifting should be held
(manual-transmission mode). When shifting of the automatic transmission 2
is performed by the gear-shift processing unit 7b according to the ON
operation of the up-shift switch 21 or the down-shift switch 22 (this
could also be an up-shift operation or down-shift operation by a shift
lever), the shift-hold-level-calculation unit 7a forcibly sets the shift
hold level to 100%. When operation of the up-shift switch 21 or
down-shift switch 22 (this could also be an up-shift or down-shift
operation by a shift lever) is not performed in case where the shift hold
level is 0%, it can be considered that the driver does not intend to
perform manual operation, so in order to maintain the
automatic-transmission mode, the shift-hold-level-calculation unit 7a
fixes the shift hold level as is at 0%. The shift hold level that is
calculated by the shift-hold-level-calculation unit 7a is used when
shifting is performed by the gear-shift processing unit 7b.

[0039] Here, the shift hold level denotes a level that increases or
decreases (i.e., changes) between 0% to 100% according to the state of
the vehicle or an operation by the driver, and assumes 100% when shifting
(a gear) is completely held (manual transmission state), and assumes 0%
in the normal automatic transmission state. The shift hold level is not
an index for selectively switching-over between the manual-transmission
mode and the automatic-transmission mode, but is for referencing the
degree of the manual-transmission mode and the degree of the
automatic-transmission mode.

[0040] An example of the calculation process for calculating the shift
hold level is shown.

[0041] In a state of [1] stepping on the accelerator pedal (state of the
actual accelerator opening degree is a preset threshold value or greater;
accelerator ON state), when the shift hold level is greater than 0%, the
shift-hold-level-calculation unit uses the equation below [Equation 1] to
perform calculation so that the shift hold level changes in a direction
toward 0% (normal automatic transmission) (between T2-T3, and between
T4-T5 in FIG. 2). Here, L1 is the current shift hold level, L0
is the previous shift hold level, and K1 is an arbitrary positive
constant (%/sec). When a state of stepping on an accelerator pedal
continues, it is considered that the driver desires automatic shifting,
so the current shift hold level L1 is changed toward the side of a
shift hold level of 0% (normal automatic transmission). When the current
shift hold level L1 is calculated from [Equation 1] to be 0% or
less, the level is set to be 0% (T5 and later in FIG. 2).

[0042] In a state of [2] returning the accelerator pedal (state wherein
the actual accelerator opening degree is less than a preset threshold
value; accelerator OFF state) when the shift hold level is greater than
0% and less than 100%, the shift-hold-level-calculation unit 7a uses the
equation below [Equation 2] to perform calculation so that the shift hold
level is changed toward 100% (shift hold) (between T3-T4 in FIG. 2).
Here, L1 is the current shift hold level, L0 is the previous
shift hold level, and K2 is an arbitrary positive constant [%/sec].
When the state of returning the accelerator pedal continues, it is
considered that the driver desires manual gear-shifting, so the current
shift hold level L1 is changed toward the side of a shift hold level
of 100% (shift hold). When the current shift hold level L1 is
calculated using [Equation 2] to be 100% or greater, the level is set to
be 100% (between T1-T2 in FIG. 2). When the shift hold level is 0% even
in a state of returning the accelerator pedal, the shift hold level will
not be updated as long as there is no operation of the up-shift switch 21
or down-shift switch 22, so the shift hold level is fixed at 0% (before
T1 and after T6 in FIG. 2).

[0043] The gear-shift processing unit 7b is a unit that has a function for
performing the shift control process of the automatic transmission. The
gear-shift processing unit 7b performs control so that when the up-shift
switch 21 is set to ON (an up-shift operation by the shift lever is also
possible), the shift gear of the automatic transmission moves up by one
gear (speed). When the shift lever is operated, the gear-shift processing
unit 7b performs gear-shift control based on a signal from the shift
position sensor 13. The gear-shift processing unit 7b performs control
such that when the down-shift switch 22 is set to ON (a down-shift
operation by the shift lever is also possible), the shift gear of the
automatic transmission moves down by one gear. The gear-shift processing
unit 7b performs shifting line processing when the up-shift switch 21 or
the down-shift switch 22 is set ON. When the up-switch 21 or the
down-switch 22 are not operated, the gear-shift processing unit 7b
acquires a real-time shift hold level that was calculated by the
shift-hold-level-calculation unit 7a, and when the level is greater than
0%, performs shifting line processing by updating the acquired shift hold
level. In this shifting line processing, the gear-shift processing unit
7b, based on the acquired shift hold level, selects a corresponding
shifting line from a shifting map (see FIG. 3) that is stored in memory
7c, and based on the selected shifting line, performs the gear-shift
control process of the automatic transmission control according to the
accelerator opening degree and the vehicle speed.

[0044] As examples of selecting a corresponding shifting line according to
the shift hold level, [1] when the shift hold level is 0 to 19%, the
gear-shift processing unit 7b selects shifting line A (shifting line for
automatic transmission; A (n→n+1), A (n→n-1)) in the
shifting map, [2] when the shift hold level is 20 to 69%, selects
shifting line N (in between shifting line A and shifting line Z; N
(n→n+1), N (n→n-1)) in the shifting map, and [3] when the
shift hold level is 70 to 100% (FIG. 3; n is the shift gear), selects
shifting line Z (shifting line for shift hold; Z (n→n+1), Z
(n→n-1)). The shifting line for shift hold Z (n→n+1), Z
(n→n-1) is a shifting line where shifting (shift up, shift down)
is performed at a specified vehicle speed regardless of the accelerator
opening degree. Moreover, the shifting line for automatic transmission A
(n→n+1) is a shifting line where shifting up is performed at a
high vehicle speed as the accelerator opening degree increases, and
shifting line A (n→n-1) is a shifting line where shifting down is
performed at a high vehicle speed as the accelerator opening degree
increases. Furthermore, on the shifting up side, the vehicle speed where
shifting is performed becomes higher in the order of the shifting line A
(n→n+1), shifting line N (n→n+1) and shifting line Z
(n→n+1), and the vehicle speed where shifting is performed becomes
low in the order of the shifting line A (n→n-1), shifting line N
(n→n-1) and shifting line Z (n→n-1). FIG. 3 illustrates an
example where three shifting lines (total of six shifting lines for
shifting up and shifting down) are used, however, as long as there are at
lease two or more shifting lines (total of four or more shifting lines
for shifting up and shifting down), any number is possible.

[0045] As examples of processing shifting control of the automatic
transmission based on selected the shifting lines according to the
accelerator opening degree and vehicle speed, the gear-shift processing
unit 7b, for example, provided that the shifting line N (N
(n→n+1), N (n→n-1) is selected performs gear-shift
processing of shifting up, [1] when the actual vehicle speed (vehicle
speed detected by the vehicle speed sensor 12) at the actual accelerator
opening degree (accelerator opening degree that is detected by the
accelerator opening degree sensor 11) is equal to or greater than the
vehicle speed that corresponds to the actual accelerator opening degree
of the shifting line N (n→n+1) on the selected shifting up side,
performs gear-shift processing of shifting down, [2] when the actual
vehicle speed is equal to or less than the vehicle speed that corresponds
to the actual accelerator opening degree of the shifting line N
(n→n-1) on the selected shifting down side, and [3] when the
vehicle speed is [3] between shifting lines (for example between N
(n→n+1) and N (n→n-1)), maintains the current shifting
gear. The same applies for shifting line A and shifting line Z.

[0046] The memory 7c is a unit that functions to store specified
information such as shifting maps, programs and the like. The memory 7c
provides information to the gear-shift processing unit 7b that
corresponds to requests from the gear-shift processing unit 7b.

[0047] The accelerator opening degree sensor 11 is a sensor that detects
the accelerator opening degree that corresponds to the amount that the
accelerator pedal (not illustrated in the figure; can also be an
accelerator lever) has been operated. The vehicle speed sensor 12 is a
sensor that detects the speed of the vehicle. The shift position sensor
13 is a sensor that detects the amount that the shift lever has been
operated (such as parking P, neutral N, drive D, shift-up +, shift-down
-). The sensors 11, 12, 13 are connected to the electronic controller 7
so that communication is possible.

[0048] The steering wheel 20 is a steering apparatus for arbitrarily
changing the traveling direction of the vehicle, and is a steering wheel
in FIG. 1. An up-shift switch 21 and down-shift switch 22 for performing
manual shifting are attached to the steering wheel 20. The up-shift
switch 21 is a switch (also called a "+ paddle") for manually shifting up
the shift gear of the automatic transmission 2. The down-shift switch 22
is a switch (also called a "- paddle") for manually shifting down the
shift gear of the automatic transmission 2. Both of the switches 21, 22
are connected to the electronic controller 7 so that communication is
possible.

[0049] Next, the operation of the shift control apparatus for an automatic
transmission of a first example of the present invention will be
explained using the drawings. FIG. 4 is a flowchart schematically
illustrating the operation of the gear-shift control apparatus for an
automatic transmission of a first example of the present invention.
Construction of a vehicle that includes a shift control apparatus for an
automatic transmission is illustrated in FIG. 1.

[0050] First, the electronic controller 7 determines whether or not the
down-shift switch 22 has been switched ON (step A1). When the down-shift
switch 22 is not ON (step A1; NO), processing advances to step A3.

[0051] When the down-shift switch 22 has been switched ON (step S1; YES),
the electronic controller 7 performs control so as to lower (shift-down)
the shifting gear (transmission gear) of the automatic transmission 2 by
one gear (shift speed) (step A2). After step A2, processing advances to
step A5.

[0052] When the down-shift switch 22 is not ON (step A1; NO), the
electronic controller 7 determines whether or not the up-shift switch 21
has been switched ON (step A3). When the up-shift switch 21 is not ON
(step A3: NO), processing advances to step A6.

[0053] When the up-shift switch 21 has been switched ON (step A3: YES),
the electronic controller 7 performs control so as to raise the shift
gear (transmission gear) of the automatic transmission 2 by one gear
(step A4). After step A4, processing advances to step A5.

[0054] After step A2 or step A4, the electronic controller 7 forcibly sets
the shift hold level in the shift-hold-level-calculation unit 7a to 100%
(step A5). Step A5 corresponds to the point in time T1 in FIG. 2. After
step A5, processing advances to step A8.

[0055] When the up-shift switch 21 is not ON (step A3: NO), the electronic
controller 7 determines whether or not the shift hold level in the
shift-hold-level-calculation unit is greater than 0% (step A6). When the
shift hold level in the shift-hold-level-calculation unit 7a is 0% or
less (step A6: NO), the shift hold level is 0%, so processing advances to
step A8 without updating the shift hold level. NO in step A6 corresponds
to points in time before T1 and after T5 in FIG. 2.

[0056] When the shift hold level in the shift-hold-level-calculation unit
7a is greater than 0% (step A6: YES), the electronic controller 7 updates
(continuously or intermittently update-processing) the value of the shift
hold level in the shift-hold-level-calculation unit 7a (step A7). After
step A7, processing advances to step A8. Step A7 corresponds to a point
in time between T1 to T5 in FIG. 2.

[0057] After step A5, after step A7 or in the case of NO in step A6, the
electronic controller 7 causes the gear-shift processing unit 7b to
select a shifting line (for example, see FIG. 3) according to most recent
shift hold level in the shift-hold-level-calculation unit 7a (100% in the
case of being after step A5, the most recent value after update in the
case of being after step A7, and 0% in the case of NO in step A6), then,
based on the selected shifting line, performs the gear-shift control
process (control process for shifting down, shifting up or maintaining
the shifting gear) of the automatic transmission 2 according to actual
accelerator opening degree (value detected by the accelerator opening
degree sensor 11) and the actual vehicle speed (value detected by the
vehicle speed sensor 12) (step A8). After step A8, processing returns to
the start.

[0058] With this first example, the transmission mode is switched
automatically according to a shift hold level that is automatically
calculated and set, so there is no need for troublesome operation upon
changing the mode, and thus it is possible to improve the ease of
operation and fuel efficiency. Moreover, switching of the transmission
mode is performed in multi stages according to a shift hold level that is
automatically calculated and set, so it is possible to improve
drivability and feeling without sudden change in the state of the vehicle
(sudden change in the shift gear). In addition, shifting is possible by
simply changing the automatic-transmission control using operation of an
up-shift switch 21 and down-shift switch 22, without the need for new
manual-transmission control, so it is possible to simplify control.
Furthermore, through operation of the up-shift switch 21 and down-shift
switch 22, it is possible to hold shifting, so it is possible to improve
ease of operation and convenience.

Example 2

[0059] A gear-shift control apparatus for an automatic transmission of a
second example of the present invention will be explained using the
drawings. FIG. 5 is a drawing for explaining shifting points that are
calculated by the gear-shift control apparatus for an automatic
transmission of this second example of the present invention.

[0060] The second example is such that the gear-shift processing unit
(corresponds to 7b in FIG. 1) of the electronic controller (7 in FIG. 1)
selects a preset shifting line (see FIG. 3) according to the shift hold
level as in the first example, then calculates the shifting point(s)
based on a shifting line(s) in a preset shifting map according to the
shift hold level and accelerator opening degree, and performs gear-shift
control processing based on the calculated shifting point according to
the vehicle speed. The other construction is the same as in the first
example.

[0061] As an example of calculating a shifting point according to the
shift hold level, when, as illustrated in FIG. 3, [1] shifting lines A
(shifting lines for automatic transmission; A (n→n+1), A
(n→n-1) when the shift hold level is 0%, [2] shifting lines N
(between the shifting line A and shifting line Z; N (n→n+1), A
(n→n-1)) when the shift hold level is 40%, and [3] shifting lines
Z (shifting lines for shift hold; Z (n→n+1), Z (n→n-1))
when the shift hold level is 100%, are stored in memory (corresponds to
7c in FIG. 1), the gear-shift processing unit (corresponds to 7b in FIG.
1) calculates the shifting point(s) as described below.

[0062] When the shift hold level is 0%, a shifting point PAD on the
shift-down side and a shifting point PAU on the shift-up side are
found on the shifting line A (A (n→n+1), A (n→n-1)) that
corresponds to the actual accelerator opening degree (value detected by
the accelerator opening degree sensor 11 in FIG. 1).

[0063] When the shift hold level is greater than 0% and less than 40%,
based on the shifting line A (A (n→n+1), A (n→n-1)) and
shifting lines N (N (n→n+1), N (n→n-1)), a shifting point
PAU on the shift-up side and a shifting point PAD on the
shift-down side are found on the shifting lines A (A (n→n+1), A
(n→n-1)) that corresponds to the actual accelerator opening degree
(value detected by the accelerator opening degree sensor 11 in FIG. 1),
and a shifting point PNU on the shift-up side and a shifting point
PND on the shift-down side are found on the shifting line N (N
(n→n+1), N (n→n-1)) that corresponds to the actual
accelerator opening degree, and by calculating each shifting point and
shift hold level value using the [Equation 3] below, the shifting point
PLU on the shift-up side and the shifting point PLD on the
shift-down side that correspond to the shift hold level L and actual
accelerator opening degree are found.

PLU={(40-L)×PAU+(L-0)×PNU}/40

PLD={(40-L)×PAD+(L-0)×PND}/40 [Equation 3]

Where:

[0064] PLU: Shifting point on the shift-up side to be calculated PLD:
Shifting point on the shift-down side to be calculated L: Shift hold
level PAU: Shifting point on the shift-up side on shifting line A
PAD: Shifting point on the shift-down side on shifting line A
PNU: Shifting point on the shift-up side on shifting line N
PND: Shifting point on the shift-down side on shifting line N

[0065] When the shift hold level is 40%, a shifting point PND on the
shift-down side and a shifting point PNU on the shift-up side are
found on the shifting line N (N (n→n+1), N (n→n-1)) that
corresponds to the actual accelerator opening degree (value detected by
the accelerator opening degree sensor in FIG. 1).

[0066] When the shift hold level is greater than 40% and less than 100%,
based on the shifting lines N (N (n→n+1), N(n→n-1)) and
shifting lines Z (Z (n→n+1), Z (n→n-1)), a shifting point
PNU on the shift-up side and a shifting point PND on the
shift-down side are found on the shifting lines N (N (n→n+1), N
(n→n-1)) that correspond to the actual accelerator opening degree,
and a shifting point PZU on the shift-up side and a shifting point
PZD on the shift-down side are found on the shifting lines Z (Z
(n→n+1), Z (n→n-1)) that correspond to the actual
accelerator opening degree (value detected b the accelerator opening
degree sensor in FIG. 1), and by calculating each shifting point and
shift hold level value using the [Equation 4] below, the shifting point
PLU on the shift-up side and the shifting point PLD on the
shift-down side that correspond to the shift hold level L and actual
accelerator opening degree are found.

PLU={(100-L)×PNU+(L-40)>PZU}/(100-40)

PLD={(100-L)×PND+(L-40)×PZD}/(100-40)
[Equation 4]

Where:

[0067] PLU: Shifting point on the shift-up side to be calculated
PLD: Shifting point on the shift-down side to be calculated L: Shift
hold level PNU: Shifting point on the shift-up side on shifting line
N PND: Shifting point on the shift-down side on shifting line N
PZU: Shifting point on the shift-up side on shifting line Z
PZD: Shifting point on the shift-down side on shifting line Z

[0068] For example, when the shift hold level L=70%, a shifting point
PLU on the shift-up side that corresponds to the shift hold level L
and actual accelerator opening degree is found using [Equation 5] below
(see FIG. 5).

PLU={(100-70)×PNU+(70-40)×PZU}/(100-40)
[Equation 5]

[0069] When the shift hold level is 100%, a shifting point PZD on the
shift-down side and a shifting point PZU on the shift-up side on a
shifting line Z (Z (n→n+1), Z (n→n-1)) that corresponds to
the actual accelerator opening degree (value detected by the accelerator
opening degree sensor in FIG. 1) are found.

[0070] Here, an example was given of using three shifting lines (total of
six shifting lines for shifting up and shifting down), however, as long
at there are two or more shifting lines (total of four or more for
shifting up and shifting down) any number could be used.

[0071] As an example of a shift control process based on the calculated
shifting point, the gear-shift processing unit (7b in FIG. 1), after
finding a shifting point PLU on the shift-up side and a shifting
point PLD on the shift-down side, for example, performs a shifting
processing of shifting up [1] when the actual vehicle speed (vehicle
speed detected by the vehicle speed sensor 12) is equal to or greater
than the vehicle speed that corresponds to the shifting point PLU on
the shift-up side, performs a shifting process of shifting down [2] when
the vehicle speed is equal to or less than the vehicle speed that
corresponds to the shifting point PLD on the shift-down side, and
maintains the current shift gear [3] when the vehicle speed is between
the shifting points PLU and PLD.

[0072] With this second example, as in the first example switching the
transmission mode is performed automatically according to a shift hold
level that is automatically calculated and set, so there is no need for
troublesome operation when changing modes, and thus it is possible to
improve the ease of operation and fuel efficiency. Moreover, switching of
the transmission mode is performed continuously according to a shift hold
level that is automatically calculated and set, so there is no sudden
change in the vehicle state (sudden gear shift), and it is possible to
improve drivability and feeling even more than in the first example. In
addition, as in the first example, with the up-shift switch (corresponds
to 21 in FIG. 1) and the down-shift switch (corresponds to 22 in FIG. 1)
it is possible to shift by just improving the automatic transmission
control without having to install new manual transmission control, so it
is possible to simplify control. Furthermore, as in the first example, by
operating the up-shift switch (corresponds to 21 in FIG. 1) and the
down-shift switch (corresponds to 22 in FIG. 1), it is possible to hold
shifting, so it is possible to improve the ease of operation and
convenience.

Example 3

[0073] The gear-shift control apparatus for an automatic transmission of a
third example of the present invention will be explained using the
drawings. FIG. 6 is a drawing for explaining correction of the
accelerator opening degree of the gear-shift control apparatus for an
automatic transmission of this third example of the present invention.

[0074] In example 3, the gear-shift processing unit (corresponds to 7b in
FIG. 1) of the electric controller (corresponds to 7 in FIG. 1) does not
perform gear-shift control processing using the value (actual accelerator
opening degree) detected by the accelerator opening degree sensor (11 in
FIG. 1) as in examples 1 and 2 as is, but corrects the actual accelerator
opening degree Accl (value detected by the accelerator opening degree
sensor) based on the shift hold level L, then performs shift control
processing based on a preset shifting line A (A (n→n+1), A
(n→n-1); shifting lines for automatic transmission with part of
the shifting line improved) according to the corrected accelerator
opening degree Aup, Adown. The other operation and construction
is the same as in the first example. Here, for the corrected accelerator
opening degree there is a corrected accelerator opening degree Aup
that is used for a shifting line A (n→n+1) on the shift-up side,
and a corrected accelerator opening degree Adown that is used for a
shifting line A (n→n-1) on the shift-down side, and is calculated
(corrected) based on the actual accelerator opening degree Accl according
to the shift hold level L.

[0075] The corrected accelerator opening degree Aup on the shift-up
side is corrected to a value that is equal to or greater than the actual
accelerator opening degree Accl according to the shift hold value. The
corrected accelerator opening degree Aup (L=0%) when the shift hold
value L=0% is made to coincide with the actual accelerator opening degree
Accl, and as the shift hold level L increases, the corrected accelerator
opening degree AUP becomes greater, and the corrected accelerator
opening degree Aup (L=100%) becomes a maximum when the shift hold
level L=100% (see FIG. 6). For example, the corrected accelerator opening
degree Aup has a relationship such as "Aup (L=100%)>Aup
(L=50%)>Aup (L=10%)>Accl". The reason that the corrected
accelerator opening degree Aup is corrected to a larger value as the
shift hold level L increases is that as the shift hold level L increases,
in order to make it difficult to shift up (make it easier to perform a
shift hold), the vehicle speed that corresponds to the shifting point is
increased. The corrected accelerator opening degree Aup, for
example, can be calculated using [Equation 6] below. When Aup
becomes equal to or greater than MA according to [Equation 6], Aup
is set so that Aup=MA.

[0076] The corrected accelerator opening degree Adown is corrected
according to the shift hold level to a value equal to or less than the
actual accelerator opening degree Accl. The corrected accelerator opening
degree Adown (L=0%) when the shift hold level L=0% is made to
coincide with the actual accelerator opening degree Accl, and as the
shift hold level L becomes larger, the corrected accelerator opening
degree Adown becomes smaller, and when the shift hold level L=100%,
the correction accelerator opening degree Adown (L=100%) becomes a
minimum (see FIG. 6). For example, Adown is in a relationship such
as "Adown (L=100%)<Adown (L=50%)<Adown
(L=10%)<Accl". The reason that the corrected accelerator opening
degree Adown is corrected so as to become smaller as the shift hold
level L become greater is because, as the shift hold level L becomes
greater, the vehicle speed corresponding to the shifting point in order
to make it difficult to shift down (make it is to perform a shift hold)
becomes low. The corrected accelerator opening degree Adown can be
calculated using [Equation 7] below. When Adown becomes equal to or
less than -K14, Adown is set to Adown=-K14. K14
is an arbitrary positive constant.

[0078] The shifting line A (A (n→n+1), A (n→n-1)) is based
on a shifting line for automatic transmission where the accelerator
opening degree is between 0 and MA0 (maximum value of the accelerator
opening degree), where the shifting line A (n→n+1) on the shift-up
side is a shifting line for shift hold on the shift-up side for an
accelerator opening degree between MA0 to MA, and shifting line A
(n→n-1) on the shift-down side is a shifting line for shift hold
on the shift-down side for an accelerator opening degree between 0 to
-K14 (see FIG. 6).

[0079] As an example of gear-shift control processing based on the
corrected accelerator opening degree Aup, Adown, the gear-shift
processing unit (7b in FIG. 1), after the corrected accelerator opening
degrees Aup, Adown having been found, for example, based on the
preset shifting lines A (A (n→n+1), A (n→n-1); the shifting
line for automatic transmission of which part of the shifting line has
been corrected), [1] performs a shifting process to shift up when the
actual vehicle speed (vehicle speed detected by the vehicle speed sensor
12) is equal to or greater than the vehicle speed corresponding to
correction accelerator opening degree Aup on the shift-up side, [2]
performs a shifting process to shift down when the actual vehicle speed
is equal to or less than the vehicle speed corresponding to the corrected
accelerator opening degree Adown on the shift-down side, and [3]
maintains the current shift gear when the actual vehicle speed is between
the vehicle speed corresponding to the corrected accelerator opening
degree Aup and the vehicle speed corresponding to the corrected
accelerator opening degree Adown.

[0080] With this third example, operation is performed to switch the
transmission mode according to a corrected accelerator opening degree
obtained by correcting the actual accelerator opening degree according to
an automatically set shift hold level, so there is no need for
troublesome operation in order to change the mode, and it is possible to
improve ease of operation and fuel efficiency. Moreover, the actual
accelerator opening degree is corrected so that it is difficult for
shifting to occur as the shift hold level increases (becomes easy to
perform a shift hold), so there is no sudden change in the vehicle state
(sudden gear shift), and it is possible to improve drivability and
feeling. In addition, as in the first example, with the up-shift switch
(corresponds to 21 in FIG. 1) and the down-shift switch (corresponds to
22 in FIG. 1) it is possible to shift by just improving the automatic
transmission control without having to install new manual transmission
control, so it is possible to simplify control. Furthermore, as in the
first example, by operating the up-shift switch (corresponds to 21 in
FIG. 1) and the down-shift switch (corresponds to 22 in FIG. 1), it is
possible to hold shifting, so it is possible to improve the ease of
operation and convenience.

Example 4

[0081] The gear-shift control apparatus for an automatic transmission of a
fourth example of the present invention will be explained using the
drawings. FIG. 7 is a time chart for explaining the change in the shift
hold level that is calculated by the gear-shift control apparatus for an
automatic transmission of this fourth example of the present invention.

[0082] The fourth example is a variation of a calculation process for
calculating the shift hold level by the shift-hold-level-calculation unit
(7a in FIG. 1) in the gear-shift control apparatus for an automatic
transmission of the first example. In the fourth example, when there is
change in the amount that the accelerator pedal is pressed (when pressed
or released) the shift hold level is corrected in the direction toward
the 100% (sift hold) side. The operation and construction other than the
shift hold calculation process is the same as in the first example.
Moreover, the fourth example can also be applied to the second and third
examples.

[0083] As in the first example, the shift-hold-level-calculation unit
(corresponds to 7a in FIG. 1) performs calculation in a state where it is
okay to return to the normal automatic transmission state
(automatic-transmission mode) so that the shift hold level is decreased
toward 0%; however, in a state where shifting should be held
(manual-transmission mode), performs calculation so that the shift hold
level increases toward 100%. Furthermore, as in the first example, when
the gear-shift processing unit (corresponds to 7b in FIG. 1) performs
shifting of the automatic transmission (corresponds to 2 in FIG. 1)
according to the ON operation by the up-shift switch (corresponds to 21
in FIG. 1) or the down-shift switch (corresponds to 22 in FIG. 1) (this
is also possible by an up-shift or down-shift operation using the shift
lever), the shift-hold-level-calculation unit (corresponds to 7a in FIG.
1) forcibly sets the shift hold level to 100%. As in the first example,
when the shift hold level is 0% and operation by the up-shift switch
(corresponds to 21 in FIG. 1) or the down-shift switch (corresponds to 22
in FIG. 1) (this is also possible by an up-shift or down-shift operation
using the shift lever), the shift-hold-level-calculation unit
(corresponds to 7a in FIG. 1), it can be said that the operation has no
intention of performing manual operation, so in order to maintain the
automatic-transmission mode, the shift hold level is kept as is at 0%.
The shift hold level that is calculated by the shift-hold-calculation
unit (corresponds to 7a in FIG. 1) is used when the gear-shift processing
unit (corresponds to 7b in FIG. 1) performs a shifting process.

[0084] An example of the calculation process for calculating the shift
hold level will be given.

[0085] When the shift hold level is greater than 0% and less than 100% in
a state where [1] the actual accelerator opening degree is equal to or
greater than a preset threshold value (accelerator ON state), the
shift-hold-level-calculation unit (corresponds to 7a in FIG. 1) uses
[Equation 8] below to perform calculation according the absolute value
|ΔAccl| of the amount of change in the amount that the accelerator
pedal is pressed (actual accelerator opening degree) so that the shift
hold level changes. Here, L1 is the current shift hold level,
L0 is the previous shift hold level, K11 and K12 [%/sec]
are arbitrary positive constants, and |ΔAccl| is the absolute value
of the amount of change in the amount that the accelerator pedal is
pressed (actual accelerator opening degree). When
K11>K12|ΔAccl|, the current shift hold level L1
changes in the direction toward the shift hold level 0% side (normal
automatic-transmission) (between T2 to T3, between T3 to T4 and between
T5 to T6 in FIG. 7), when K11<K12|ΔAccl|, the current
shift hold level L1 changes in the direction toward the shift hold
level 100% side (shift hold), and when K11=K12|ΔAccl|,
the current shift hold level L1 is the same as the previous shift
hold level L0. When the amount that the accelerator pedal is pressed
is always changing, such as when the automobile is travelling over a
winding road, there is a possibility that the driver desires to perform
manual shifting, so the absolute value |ΔAccl| of the amount of
change in the amount that the accelerator pedal is pressed (actual
accelerator opening degree) is such that current shift hold level L1
is changed toward shift hold level 100% (shift hold) side. As in the
first example, when the amount that the accelerator pedal is pressed is
in a fixed state (|ΔAccl|=0), the current shift hold level L1
changes toward the shift hold level 0% (normal automatic transmission)
side (between T2 to T3 in FIG. 7). When, according to [Equation 8], the
current shift hold level L1 is equal to or less than 0%, the L1 is
taken to be 0%.

[0087] When the shift hold level is greater than 0% and less than 100% in
a state where [2] the actual accelerator opening degree is less than
preset threshold value (includes a state where the accelerator is OFF,
and a state when the accelerator pedal is released), the
shift-hold-level-calculation unit (corresponds to 7a in FIG. 1) uses
[Equation 9] below to perform calculation so that the shift hold level
changes in a direction toward the 100% (shift hold) side (T4 to T5, and
T6 and later in FIG. 7). Here, L1 is the current shift hold level,
L0 is the previous shift hold level, and K21 [%/sec] is an
arbitrary positive constant. When the accelerator is OFF, it is thought
that the driver desires to perform manual shifting, so the current shift
hold level L1 is changed to the shift hold level 100% (shift hold)
side. When according to [Equation 9] the current shift hold level L1
is 100% or greater, it is taken to be 100% (T1 to T2 in FIG. 7).
Moreover, when the shift hold level is 0% even when the accelerator is
OFF, the shift hold level will not be updated unless the up-shift switch
(corresponds to 21 in FIG. 1) or the down-shift switch (corresponds to 22
in FIG. 1) is operated, so the shift hold level is fixed at 0% (T1 and
before in FIG. 7).

[0089] The shift hold level that is calculated as described above is
changed or updated according to the flowchart in FIG. 4, and is used by
the gear-shift processing unit (7b in FIG. 1) when processing shifting
control.

[0090] With this fourth example, together with obtaining an effect similar
to the first example, by calculating the shift hold level according to
the absolute value of the change in the amount that the accelerator pedal
is pressed when the accelerator is ON, it is possible to achieve shifting
that reflects the potential intention of the driver.

Example 5

[0091] The gear-shift control apparatus for an automatic transmission of a
fifth example of the present invention will be explained using the
drawings.

[0092]FIG. 8 is a block diagram that schematically illustrates the
construction of a vehicle that includes the gear-shift control apparatus
for an automatic transmission of a fifth example of the present
invention. FIG. 9 is a time chart for explaining the change in the shift
hold level that is calculated by the gear-shift control apparatus for an
automatic transmission of this fifth example of the present invention.

[0093] This fifth example is an example of a variation of the calculation
process for calculating the shift hold level by
shift-hold-level-calculation unit (7a in FIG. 1) of the gear-shift
control apparatus for an automatic transmission of the first example. In
the fifth example, [1] when the shift hold level is greater than 0% in a
state where the automobile is traveling at constant speed (in coasting)
or accelerating on a flat road and the amount that the accelerator pedal
is pressed is constant, the shift hold level is changed in the direction
of normal automatic transmission (shift hold level 0% side); [2] when the
shift hold level is greater than 0% even in a state where the automobile
is accelerating on an uphill road, or accelerating on a downhill road and
the amount that the accelerator pedal is pressed is constant, the shift
hold level is changed in the direction toward normal automatic
transmission (shift hold level 0% side); and [3] when the shift hold
level is greater than 0% and less than 100% in other states, the shift
hold level is changed in the direction toward 100%. The fifth example
differs from the first example (see FIG. 1) in that a gradient detection
device (14 in FIG. 8) that detects (can also calculate) the gradient
(incline) of the road is added. The operation and construction for other
than the process for calculating the shift hold level is the same as in
the first example. This fifth example can also be applied to the second
and third examples.

[0094] The gradient detection device 14 is a device that detects the
gradient (incline) of the road over which the automobile is traveling. It
is possible to use, for example, a gyrocompass that detects gradient
using the gyroscopic effect as the gradient detection device 14, or it is
also possible to use a device that estimates (calculates) the gradient
based on the driving power of the engine, the vehicle speed, and the
vehicle weight. The gradient detection device 14 is connected so that
communication with the electronic controller 7 is possible. Information
related to the gradient that was detected by the gradient detection
device 14 is used in the process by the electronic controller 7 for
calculating the shift hold level.

[0095] As in the first example, the shift-hold-level-calculation unit 7a
performs calculation to reduce the shift hold level toward 0% when it is
okay to return to the normal automatic transmission state
(automatic-transmission mode), and on the other hand, performs
calculation to increase the shift hold level toward 100% when shifting
should be held (manual-transmission mode). Moreover, the
shift-hold-level-calculation unit 7a, as in the first example, forcibly
sets the shift hold level to 100% when shifting of the automatic
transmission 2 is performed by the gear-shift processing unit 7b
according to an ON operation of the up-shift switch 21 or down-shift
switch 22 (an up-shift operation or down-shift operation using the shift
lever is also possible). As in the first example, when the shift hold
level is 0%, and when operation of the up-shift switch 21 or down-shift
switch 22 is not performed (this could be an up-shift or down-shift
operation by the shift lever), it can be said that the driver has no
intention to perform manual shifting, so the shift-hold-level-calculation
unit 7a fixes the shift hold level as is at 0% in order to maintain the
automatic-transmission mode. The shift hold level that is calculated by
the shift-hold-level-calculation unit 7a is used when shifting is
performed by the gear-shift processing unit 7b.

[0096] An example of the calculation process for calculating the shift
hold level will be given.

[0097] When calculating the shift hold level, the
shift-hold-level-calculation unit 7a, based on the vehicle speed that is
detected by the vehicle speed sensor 12, calculates the accelerator
opening degree A0 that is necessary for the vehicle to travel at
constant speed, and based on the calculated accelerator opening degree
A0 and the gradient calculated by the gradient detection device 14,
calculates the upper limit value (A0+R1) and the lower limit
value (A0-R3) of the accelerator opening degree necessary for
traveling at constant speed. R1 and R3 are positive values.

[0098] Here, the accelerator opening degree A0 that is necessary for
traveling at constant speed depends on the vehicle speed, and is in a
relationship where as the vehicle speed increases, the accelerator
opening degree A0 increases. R1 at the upper limit value of the
accelerator opening degree necessary for traveling at constant speed
depends on the absolute value of the incline, and is in a relationship
where as the absolute value of the gradient increases, R1 increases.
R3 at the lower limit value of the accelerator opening degree
necessary for traveling at constant speed depends on the absolute value
of the gradient, and is in a relationship where as the absolute value of
the gradient increases, R3 decreases. The
shift-hold-level-calculation unit 7a performs calculation so that [0]
when the actual accelerator opening degree (value detected by the
accelerator opening degree sensor 11) is equal to or greater than the
upper limit value (A0+R1) of the accelerator opening degree,
and the shift hold level is greater than 0% and less than 100%, [Equation
10] is used and the shift hold level is changed according to the absolute
value of the difference between the actual accelerator opening degree and
the upper limit value (A0+R1) of the accelerator opening degree
necessary for traveling at constant speed, and according to the absolute
value of the amount of change that the accelerator pedal is pressed
(actual accelerator opening degree) (see a range of T3 to T6 in FIG. 9).
Here, L1 is the current shift hold level, L0 is the previous
shift hold level, K01, K02 and K03 [%/sec] are arbitrary
positive constants, |ΔAccl| is the absolute value of the amount of
change in the amount the accelerator pedal is pressed (actual accelerator
opening degree), Accl is the accelerator opening degree (amount the
accelerator has been pressed), A0 is the accelerator opening degree
necessary for traveling at constant speed, and A0+R1 is the
upper limit value of the accelerator opening degree necessary for
traveling at constant speed (R1 is a positive value). When
"K01>K02|ΔAccl|+K03|ΔAccl-(A0+R1)-
|", the current shift hold level L1 changes in the direction toward
the shift hold level 0% side (normal automatic transmission (see a range
of T5 to T6 in FIG. 9), when
"K01<K02|ΔAccl|+K03|ΔAccl-(A0+R1)-
|", the current shift hold level L1 in the direction toward the shift
hold level 100% side (shift hold) (see a range of T3 to T4 in FIG. 9),
and when "K01=K02|ΔAccl|+K03|ΔAccl-(A0+R.-
sub.1)|", the current shift hold level L1 is the same as the previous
shift hold level L0 (see T5 in FIG. 9). When the accelerator pedal
is being pressed in order to accelerate on a uphill slope, there is a
possibility that the driver desires to perform manual shifting, so the
absolute value |Accl-(A0+R1)| of the difference between the
actual accelerator opening degree and the upper limit (A0+R1)
of the accelerator opening degree necessary for traveling at constant
speed functions so as to change the current shift hold level L1 to
the shift hold level 100% (shift hold) side. When the amount that the
accelerator is pressed is always changing such as during traveling on a
winding road, there is a possibility that the driver desires to perform
manual shifting, so the absolute value |ΔAccl| of the amount of
change in the amount that the accelerator pedal is pressed (actual
accelerator opening degree) functions so that the current shift hold
level L1 changes to the shift hold level 100% (shift hold) side. The
current shift hold level L1 is taken to be 100% when according to
[Equation 10] it is 100% or greater (refer to T4 to T5 in FIG. 9), and is
taken to be 0% when it is 0% or less.

[0100] The shift-hold-level-calculation unit 7a performs calculation using
[Equation 11] below so that [1[ when the actual accelerator opening
degree (value detected by the accelerator opening degree sensor 11 is
between the upper limit value (A0+R1) and the lower limit value
(A0-R3) of the accelerator opening degree and the shift hold
level is greater than 0% and less than 100%, the shift hold level changes
according to the absolute value of the amount of change in the amount
that the accelerator pedal is pressed (actual accelerator opening degree)
(refer to T6 and later in FIG. 9). Here, L1 is the current shift
hold level, L0 is the previous shift hold level, K11 and K12
[%/sec] are arbitrary positive constants, and |ΔAccl| is the
absolute value of the amount of change in the amount that the accelerator
is pressed (actual accelerator opening degree). When
"K11>K12|ΔAccl|", the current shift hold level L1
changes in the direction toward the shift hold level 0% (normal automatic
transmission) side (refer to T6 and later in FIG. 9); when
"K11<K12|ΔAccl|", the current shift hold level L1
changes in the direction toward the shift hold level 100% (shift hold)
side; and when "K11=K12|ΔAccl|", the current shift hold
level L1 is the same as the shift hold level L0. When the
amount that the accelerator pedal is pressed is always changing such as
during traveling over a winding road, there is a possibility that the
driver desires to perform manual shifting, so the absolute value
|ΔAccl| of the amount of change in the amount that the accelerator
pedal is pressed (actual accelerator opening degree) acts such that the
current shift hold level L1 changes to the shift hold level 100%
(shift hold) side. When the amount that the accelerator pedal is pressed
is constant (|ΔAccl|=0), the current shift hold level L1
changes toward the shift hold level 0% (normal automatic transmission)
side as in the first example (see T6 and later in FIG. 9). The current
shift hold level L1 is taken to be 100% when according to [Equation
11] it is 100% or greater, and is taken to be 0% when it is 0% or less.

[0102] The shift-hold-level-calculation unit 7a uses [Equation 12] below
to perform calculation so that [2] when the actual accelerator opening
degree (value detected by the accelerator opening degree sensor 11) is
equal to or less than the lower limit value of the accelerator opening
degree (A0-R3) (accelerator OFF state; including the state of returning
the accelerator pedal), and when the shift hold level is greater than 0%
and less than 100%, the shift hold level changes according to the
absolute value of the amount of change in the difference between the
actual accelerator opening degree and the lower limit value
(Ao-R3) that is necessary for traveling at constant speed, and
the absolute value of the amount of change in the amount that the
accelerator pedal is pressed (actual accelerator opening degree) (refer
to a range of T2 to T3 in FIG. 9). Here, L1 is the current shift
hold level, L0 is the previous shift hold level, K21, K22
and K23 [%/sec] are arbitrary positive constants, |ΔAcc1| is
the absolute value of the amount of change in the amount that the
accelerator pedal has been pressed (actual accelerator opening degree),
Accl is the accelerator opening degree (amount that the accelerator has
been pressed), A0 is the accelerator opening degree necessary for
traveling at constant speed, and A0-R3 is the lower limit value
of the accelerator opening degree necessary for traveling at constant
speed (R3 is a positive value). The larger |ΔAccl| and/or
|Accl-(A0-R3)| becomes, a speed at which the current shift hold
level L1 changes in the direction toward the shift hold level 100% (shift
hold) side increases. When the depressing on the accelerator pedal is
lessened or returned such as when applying an engine break during going
downhill, there is a possibility that the driver desires to perform
manual shifting, so the absolute value |Accl-(A0-R3)| of the difference
between the actual accelerator opening degree and the lower limit value
(A0-R3) of the accelerator opening degree necessary for traveling at
constant speed functions such the current shift hold level L1
changes to the shift hold level 100% (shift hold) side. When the amount
that the accelerator pedal is pressed is always changing such as during
traveling on a winding road, there is a possibility that the driver
desires to perform manual shifting, so the absolute value |ΔAccl|
of the amount of change in the amount that the accelerator pedal is
pressed (actual accelerator opening degree) function such that the
current shift hold level L1 changes to the shift hold level 100%
(shift hold) side. When the current shift hold level L1 is equal to or
greater than 100% according to [Equation 12], it is taken to be 100%
(refer to a range of T1 to T2 in FIG. 9). Moreover, when the shift hold
level is 0% even in the accelerator OFF state, the shift hold level is
not updated unless there is an up-shift switch 21 or down-shift switch 22
operation, so the shift hold level is fixed at 0% (refer to T1 and
earlier in FIG. 9).

[0103] The shift hold level that is calculated as described above is
changed or updated according to the flowchart in FIG. 4, and is used when
the gear-shift processing unit 7b is performing shifting control.

[0104] With the fifth example, together with obtaining the same effect as
in the first example, it is possible to obtain shifting that reflects the
implicit intention of the driver when the vehicle is traveling over a
road with an incline by calculating the shift hold level according to the
incline of the road, the vehicle speed, the accelerator opening degree,
and the absolute value of the amount of change in the amount that the
accelerator pedal is pressed.

[0105] The disclosures of the Patent Literatures above are incorporated in
this specification by reference thereto. Examples and changes and
modifications to the examples are possible within the framework and the
fundamental technical scope of the entire disclosure of the present
invention (including claims and drawings). Moreover, various combinations
and selections of the disclosed elements are possible within the scope of
the claims of the present invention. In other words, the present
invention includes all variations and modifications that can be obtained
by one skilled in the art according to the entire disclosure, including
the claims, and the technical scope of the invention.